Applies to: SENSEI SENSEI RX/CX Non-SENSEI
What you can safely check
- Check gas valves are fully open and, on propane, that the tank has gas.
- Check outside vent caps are clear.
What a technician will look at
Everything past the checks above involves gas pressure, live electrical parts or opening the sealed cabinet. That work is for a licensed gas or plumbing professional. For code 12, Rinnai’s service steps cover:
- inlet gas pressure
- vent joints and recirculation of exhaust
- flame rod, gas valve and PC board
Smell gas? Don’t touch switches or try to reset the heater. Leave the building and call your gas supplier or 911 from outside.
Source: Rinnai, Troubleshooting Tankless Water Heater Diagnostic Codes (document 100000652), page 20. The code name is Rinnai’s; the explanation is ours. Codes differ between series – check the model on your heater’s rating plate. This site is independent and not affiliated with Rinnai.